Voltage-regulating system for vapor-rectifiers.



W. TSCHUDY 6; S. W. FARNSWORTH. VOLTAGE REGULATING SYSTEM FOR VAPORRECTIFIERS.

APPLICATION FILED FEB. [9.1914.

Patented Feb. 26, 1918.

WITNESSES:

Zia 4M INVENTORS ATTORNEY UNITED STATES P TENT OFFICE.

WILLIAM TSCHUDY, or wILKINsBun, AND smNEY w. EAnNswonTH, or PITTSBURGH,PENNSYLVANIA, ASSIGNORS To WESTINGHOUSE ELECTRIC AND MANUFACTURINGCOMPANY, A CORPORATION or PENNSYLVANIA.

VOLTAGE-REGULATING SYSTEM FOR VAPOKRECTIFIERS.

Specification of Letters Patent.

Patented Feb. 26, 1918 Application filed February 19, 1914. Serial No.819,691.

To all whom it may concern:

lie it known that we, WILLIAM TSCHUDY, a citizen of the Swiss Republic,and a resident of Wilkinsburg, in the county of Allegheny and State ofPennsylvania, and SID- NEY W. 'FARNswonTn, a citizen of the UnitedStates, and a resident of Pittsburgh, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inVoltage-Regulating Systems for Vapor-Rectifiers, of which the followingis a specification.

Our invention relates to current-rectifying systems and it hasparticular reference to such systems as embody vapor rectifiers of largecapacity.

The object of our invention is to provide novel and effective means forregulating the voltage, in the direct-current circuit to which. therectifier supplies current, while the voltage in the alternating-currentsupply circuit remains constant. A

In the accompanying drawing, Figure 1 is a diagrammatic view of a systemembodying our invention; Fig. 2 is a diagrammatic view of a portion ofthe system shown in Fig. 1, illustrating a modified form of loadconnection; and'Fig. 3 is a partly broken perspective view. of athermostatic control device that may be included in our system.

The rectification of alternating currents by means of a vapor rectifieris attended by a drop in potential across the rectifiery'and we havediscovered that the amount of this drop is dependent upon thetemperature at which the rectifier cathode is maintained. The drop inpotential increases as the temperature is lowered, and it may be stated,in a general way, that the amount of potential drop varies inverselywith the cathode temperature' It is customary, when a metal caserectifier is employed, to supply water or other cooling fluid to thecasing, and the amount of potential drop across the rectifier may beregulated by varying the temperature, or the amount of'the coolingmedium so supplied. For example, we have found that, in a rectifierdelivering a direct current of 200 amperes, the Voltage drop when thecooling water is supplied at 27 C. is 20 volts, while, when the coolingwater is sup lied at 56 C., the drop is only 12 volts.-

he temperature of the anode is the same under both conditions, thoughother tests have shown that the drop is not affected by changes in thetemperature of the'anode, if

the cathode temperature remains constant.

We have taken advantage of this variation in voltage drop with variationin the cathode temperature to obtain regulation of the direct-currentvoltage, and current when the alternating current is supplied at a constant voltage.

Referring now to Fig. 1 of the drawing, two single unit rectifier tanks1 and 2 are shown, each containing a main anode 3, an auxiliarymaintaining or keep-alive anode 1, and a vapori zable cathode 5. Eachtank is surrounded by a second tank or jacket 6, spaced therefrom, meansbeing provided for introducing a cooling fluid, such as water, into thespace between the tanks. As shown on the drawing, the fluid supplyingmeans comprises pipes 7 and 8 leading respectively to the jacketssurrounding the rectifiers 1 and 2 and a supply pipe 9 having a valve10.

Alternating current is supplied to the rectifier units from anyconvenient source 15, which may be the secondary winding of atransformer, and the direct current from the rectifiers is delivered byconductors 16, 17 and 18 to an external work circuit that is connected,by a conductor 19, to the middle point of the transformer winding 15.

The valve 10 is opened and closed by a lever 25 which is operativelyconnected to the movable core 26 of a coil 27. The coil 27 is connectedin series with the direct-current conductor 18. A spring 29 is attachedto the solenoid core 26 and tends to hold the core in such position thatthe valve 10 shall be closed.

The direct-current circuit may include any suitable translating devices.For pur poses of illustration, we have shown a series of arc lamps 30 asconstituting a variable direct-current load.

It will be understood that the direct current delivered by therectifiers will energize the solenoid 27 to draw its core 26 upwardly toa greater or less extent, according to the amount of current supplied tothe solenoid. This movement of the core 26 will effect the opening ofthe valve 10 to a corresponding degree. Water will therefore be suppliedto the rectifier jackets in greater amounts, as the current in thedirect current circuit increases, and in less amounts as this currentdecreases. The variation in the water supply and the consequentalteration in t e cathode temperature will cause a correspondingvariation in the voltage drop across the rectifier. The seriesconnection of the solenoid 27, shown in Fig. 1, is especially desirablefor work where constant current is to be maintained in thedirect-current circuit.

The system shown in Fig. 1 may be varied by connecting the differentelements of the load in parallel relation, instead of in seriesrelation. Such an arrangement is shown in Fig. 2, in which a solenoidcoil 27 when energized, pulls a core 26 against the tension of a spring29, and in which motors 31 and 3:2 are/shown connected across thedirectcurrent circuit. This arrangement is especially advantageous whenit is desired to maintain constant potential in the directcurrentcircuit under varying conditions of current consumption.

Advantage may be taken of the systems which we have shown either tomaintain a constant current in the direct-current circuit or to maintaina constant voltage in the direct-current circuit, with a varying load.If, for example, it is desired to supply a vari ble series ofconstant-current devices such as the arc lamps 30 of the Fig. 1, it willbe necessary to increase the applied direct-current voltage in order toprovide a constant current for the lamps as the resistance is increasedby increasing the number of lamps in circuit. This may be accomplishedin our system, because, as the resistance increases in the circuit thatincludes lamps, the current through the solenoid 27 is decreased and thevalve correspondingly partly closed to check the flow of water to therectifiers. The cathode temperature therefore rises, the voltage dropacross the rectifier decreases, and the applied directcurrent voltage isincreased proportionately.

If it is desired to maintain a constant voltage in the direct-currentcircuit while trans lating devices, such for example, as the motors 31and 32, Fig. 2, are taking current in varying amounts, the solenoid 27-will be energized less strongly when both the motors are operating thanwhen only one motor is operating, and the valve 10 will consequently beopened wider, thusincreasing the supply of cooling water. If thisincrease in water supply were directly proportional to the increase incurrent, the heat generated in the rectifier by the increased currentwould be dissipated at the same rate as before, and the voltage dropacross the rectifier would therefore remain substantially constant. Itis necessary, therefore, that the solenoid or the valve shall be sodesigned that the flow of water will increase at a somewhat slower ratethan that at which the current increases, so that the cathode may beslowly heated, thus reducing the voltage drop across the rectifier andallowing the applied direct-current voltage to be gradually increased atthe desired rate.

The systems shown in Figs. 1 and 2 will effect automatic adjustment ofthe electrical condition of the direct current circuit in the mannerdescribed above, provided the cooling medium supplied to the cathode isalways of the same temperature. However, when water is used as a coolingmedium, its temperature is likely to vary with the season of the year orwith a change in the weather at any season. It may therefore be founddesirable to provide means for compensating for these changes in thetemperature of the feed water, and we have shown a suitable device ofthis character in Fig. 4 of the drawing, in which the valve 10 isinclosed in a chamber 41 from which the feed water passes through a pipe9" and through any suitable intermediate pipe connections to therectifier jackets 6. The valve-operating lever .25 is oscillated by asolenoid 27* through a lever 42, a shaft 43, a lever 44, a twopartconnecting rod 45 and a bi-metallic thermo-couple 46 that is interposedbetween the two parts of the rod 45. It will be readily understood thatany change in the temperature of the feed water delivered to the chamber41 will cause a corresponding variation in the shape of the bi-metalliccouple 46. For example, if the feed water should increase intemperature, the curvature of the couple shown on the drawing would becorrespondingly increased, thus in effect increasing the effectivelength of the rod 45 and causing the valve to open slightly, to increasethe supply of feed water in roportion to the rise in temperature.

he thermostati control device which we 5 have shown and described formsno part of our invention, and is fully set forth and claimed in aco-pending application of David C. Davis, Serial No. 834,543, filed Aril25, 1914, and assigned toWestinghouse 10 E ectric & ManufacturingCompany.

Our system is capable of many variations within the scope of ourinvention. For exam 1e, it may include either single-unit or multipleunit rectifiers, and the rectifiers may be supplied with eithersingle-phase or polyphase alternating current. Furthermore, means otherthan the solenoid control, which We have shown, may be employed toregulate the supply of cooling fluid, our invention comprehendingbroadly all devices for varying the supply of cooling fluid in responseto variations of current or voltage in the direct-current circuit.

We claim as our invention:

1. A rectifier system comprising a source of constant-potentialalternating current, a vapor rectifier havin a cathode adapted to becooled to a variab e extent, a circuit connected to receive directcurrent from the rectifier, and means dependent upon the directcurrentcircuit for supplying a cooling medium to the rectifier cathode invarying amounts.

2. A rectifier system comprising a source of constant-potentialalternating current, a vapor rectifier provided with a cooling jacket,means for introducing a cooling medium into the said jacket, a valve forregulating the amount of cooling medium so introduced, a circuitconnected to receive direct current from the rectifier, and meansdependent upon the direct current circuit for operating the said valve.

3. A rectifier system comprising a source of constant-potentialalternating current, a vapor rectifier provided with a cooling jacket,means for introducing a cooling medium into the said jacket, a valve forcontrolling the amount of cooling medium so introduced, a circuitconnected to receive direct current from the rectifier and includingasolenoid, and means for applying the power of the solenoid to the valve.

st. A rectifier system comprising a source of constant-potentialalternating current, a vapor rectifier provided with a cooling jacket,means for introducing a cooling medium into the said jacket, a valve forcontrolling the amount of cooling medium so introduced, a circuitconnected to receive direct current from the rectifier and including asolenoid, and means for applying the power of the solenoid to the valve,whereby the valve is caused to open as the current in the direct currentcircuit increases and to close as the current in the direct currentcircuit, decreases.

5. A rectifier system comprising a source of constant-potentialalternating current, a vapor recifier means for applying a coolingmedium to the cathode of. the rectifier, a circuit'connected to receivedirect current from the rectifier and including a load having variableresistance, and means dependent upon the current in the direct-currentcircuit for keeping constant the current delivered to the load byvarying the supply of said cooling medium.

6. The combination with a vapor rectifier, of voltage-regulatingmeansassociated therewith and functioning by virtue of the cathodetemperature and resultant arc drop.

7. The combination with a vapor rectifier, of a load circuit connectedthereto, and means for regulating the arc drop therein, said means beingsubject to the control of said load circuit.

8. The method of regulating an electric circuit supplied from a vaporrectifier which comprises regulating the voltage drop in said rectifierin accordance with the current in said circuit.

In testimony whereof, We have hereunto subscribed our names this 14thday of Feb, 1914.

WILLIAM TSCHUDY; SIDNEY W. FARNSWORTH.

lVitnesses:

DAVID E. CARPENTER, B. B. HINES.

